Technical Abstract:
Escalating fossil fuel cost and concern over global climate change have accelerated interest in cellulosic feedstocks, such as corn cobs, for liquid fuel production. Little information is available about corn cob yield and its N and C content. Available cob data was compiled and summarized from several field studies conducted in the Central Great Plains. Two locations in Colorado and two in Texas that had multiple N fertilizer treatments, varying tillage systems, and different growing seasons were evaluated. Cob to grain yield ratio, cob:ear ratio and cob:stover ratio, and cob N and C uptake were determined for each site. Cob yield generally increased with increasing N rate. At the high N rates, cob yield ranged from 1290 to 1960 lb/A. Cob:stover ratio ranged from 0.14 to 0.25 at high N fertilizer levels. The N concentration varied little among N levels at any location, varying more among locations and year, ranging from 0.025 to 0.052 %. Nitrogen uptake at the highest N-levels ranged from 4.2 to 7.5 lb N/A. The relationship between final grain yield at 15.5 % water content and oven-dried cob yield was linear (r2=0.74) such that cob yield increased 5.35 lb/A for each 1 bu/A increase in grain yield. This study provides basic information on cob yield and quality for agronomists and examples are discussed on how the data could be useful for determining the feasibility of harvesting corn cobs as a cellulosic feedstock.